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J. G. CAPSTAFF.

PHOTOGRAPHS IN COLOR AND METHOD OF MAKING THE SAME.

APPLICATION FILED SEPT-21,1914.

Patented Aug. 29, 1916.

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EMA M622 m w d M a r F r k m mu m 6 5 w 0 h w a w 2 J 4 w Black 626642"i law A TTOH/VE r5 JOHN G. CAPS'IAFF, 0F ROGHESTER, NEW YORK, ABSIGNOBT0 E-ZhfiTIvIAN KQDAE. COMPANY, OF ROCHESTER, NEW YORIQ A CORPORATION OFNEW YQEIK- PHOTOGRAPHS IN COLOR AND METHOD GE IYIJKKING THE SAME}.

Specification of Letters Patent. I Patentgdt Aug, 29, 199 153,

Application filed September 21, 1914. Serial No. 862,715.

To aZZ '20 7mm it may concern;

Be it known that I, JOHN G. CAPSTAFF, of Rochester, in the county ofMonroe and State of New York, have invented certain new and usefulImprovements in Photographs in Color and Methods of Making the Same; andI do hereby declare the following to be a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings, forming a part of this specification, and to thereference-numerals marked thereon.

My present invention relates to photography and more particularly to theproduction of photographs in color and it has for its object to providea simple and convenient method of making photographic transparencies intwo or more colors, which method may be successfully practised with theskill of the ordinary photographer and Without the use of special takingapparatus or a specially prepared sensitized medium, the plates andcameras already in general use being adequate for the purpose. Featuresof novelty reside, further, in the article itself resulting from thecarrying out of my process and it, therefore, is also part of thepresent invention.

To these and other ends the invention consists in certain improvementsand combinations of parts all as will be hereinafter more fullydescribed, the novel features being pointed out in the claims at the endof the specification.

To first give a general idea of the lines along which my inventionproceeds, it may be stated preliminarily that I utilize the idea oftreating a plurality of different color sensation records of a givensubject in such manner that when subjected to certain dye solutions,they will each partly absorb and partly repel the particular dye appliedaccording to the sensations they have recorded and thus whileconstituting substantial duplicates of each other in image outline theywill constitute complements of each other in the matter of color andintensity. Their composite eflect, therefore,when superposed and viewedby transmitted light, will show instances of predominance of each coloras Well as the predominance of neither due to their neutralizing eliectupon each other, and the absence of both, the last named conditionssupplying the light and shade values.

I shall first describe my method in connection with the production oftwo color pictures, say in red and green, as this is its simplest formand result.

In practising my invention I first obtain two negatives of the subjectto be re reduced upon sensitive films, the sensitive liody beingcomposed of panchromatic silver bromoiodid suspended in a suitablevehicle such as gelatin, hereinafter termed sensitized gelatin films. Iprefer to do this by successive exposures through the same lens with theordinary apparatus or one modified only to the extent of adapting it forthe reduction to a minimum of the time interval be tween exposures, butit is obvious that the components may be obtained in other ways. By filmI mean the word in its original sense, that is, a light sensitive saltsuspended in a colloid such as gelatin whether upon'a base of glass or aflexible support. One negative is made mainly by the green lightreflected by the subject and the other mainly gives a very pleasing bythe red light, preferably through the use of red and green filtersapplied to the lens. The two negatives are developed and washed asusual. I then submit the megatives to a bleaching and tanning bath whichconverts the free silver into a salt of silver which is subsequentlyremoved in a hypobath, and leaves the films practically clear,transparent and almost colorless except for a. faint brownish trace ofthe original image. The bath preferably consists of the followingsolution:

A. Potassium ferricyanid 37. 5 gms.

br0mid 56.25 bichromate. 37. 5 Acetic (or similar) acid 10 co. Water 1,000 cc. B. ?otassium alum 5 For use take equal parts of A and B. Thesolution may be diluted by adding water.

The bath may be applied at ordinarytemperatures and the solution Washedback and forth across the film by rocking the tray as usual inphotographic manipulations until the results quoted are obtained. Asidefrom the conversion of the silver into its salt, the bleaching stepbrings about another rather more important change. Peculiar chemicalreactions that set in have the effect of tanning or similarly affectingthe gelatin in the tit? sail

immediate neighborhood of each silver particle attacked so that whatwere the black portions of the original negative film are renderedsubstantially impenetrable to the dye that is next applied,substantially in proportion to the amount of silver origi trodes uponthose parts that ought to remain clear.

An acid dye, (preferably a salt of a sulfonic acid) is used and in thetwo color method being followed, two baths are provided; one anorange-red and the other a blue-green. The red sensation record, thatis, the film exposed through the red filter, is, by submersion, dyedgreen, while the green sensation record exposed through the green filteris similarly dyed red. The distribution of the silver particles andhence of the tanned or otherwise afiected portions on the'two films isdiversified according to the (lifierent color values they respectivelyrecord and hence the dye takes effect partly at the same and partly atdifi'erent relative points. fit this point, the films may be rinsedagain in water to remove the superfluous dye and quickly dried with theaid of preliminary blotting or squegeeing to prevent lateral. difiusionof the dye and a resulting lack of good definition, but more preferablythey are treated with dilute acid which has the effect of what may betermed fixing the dye with even better results. In fact, the acidtreatment is greatly preferable particularly where this invention ispractised for the production of cinematograph film in color where, fromtheir very nature, it is diliicult to conveniently and quickly handlefor drying, the great lengths of film while any lack of definition inthe small pictures is, 01"" course, greatly, aggravated when they appearon the projecting screen.

When the two dried films are superposed upon each other with the imagesin exact register and the combination is viewed by transmitted light, itwill be seen that a positive reproduction of the subject with the black,white, red, green and various inter mediate values of its color schemereproduced will result. Since the green filter absorbs red light, allred portions of the original subject produced little or no effect uponthe sensitive film emulsion; hence these remained substantially untannedand subsequently absorbed red dye. The red filter, however, transmittedthe red light and in consequence, the red objects were recorded Illtanned by the bleaching, subsequently ab sorbed deeply the red dye. Thered filter made it appear light (to the eye) and hence recorded it darkor silvered on the other film which portion being tanned did not absorbthe green dye but remained clear.

superposition would therefore allow the red 5 to show throughunobstructed and to predominate the area of the ositive imagecorresponding to the red oi the subject. reverse would be true with thegreen color in the subject. In the same way. the reproduction of theblack and white of the subject with black and white to correspond in thefinished picture can be traced, the black resulting from an opacity dueto the neutralizing effect of deep red and deep green superposed and thewhites and grays from a total lack of the predominance of either.

In the accompanying drawing I have shown diagrammatic views illustratingroughly the steps of the method in making a picture of a colored objectcontaining only the two colors, red and green, and also white and blackareas, and have indicated by the conventional shading and by words, thecoloring or lack of color the respective parts are given or assume afterthe treatments indicated thereon. Figure 1 indicating the object; Fig. 2a diagram of the negative formed when exposed through the red filter;Fig. 3 a diagram of the same negative 1 after bleaching and fixing; Fig.diagram of the same after dyeing in the green bath; Fig. 5 a diagram ofthe negative made through the green filter; Fig. 6 a diagram of thenegative after bleachin and fixing; Fig. 7 a diagram of the same a fiterdyeing in the red bath; Fig. 8 a diagram of the composite image when theparts shown in Figs. 4 and 7 are superposed and viewed by transmittedlight.

The fixing of the two films to remove the silver salts, preceded andfollowed, of course, by washing-preferably occurs immediately after thebleaching step, for while the films may be fixed after the development,as usual, and before the bleaching, such fixing constitutes a reallyunnecessary step at that point for the reason that the bleachingsolution, in dissolving the silver, re-precipitates it in the form ofsilver bromid and fixing must therefore follow the bleaching anyway,while it is immaterial to the action of the bleach whether the developedfilm has been previously fixed or not.

Where a third color is desired, a tricolor process is worked in the sameway, a third color sensation negative being produced, bleached andsuitably dyed and the dye image superimposed upon the other two.preferably the gelatin film of this third component is stripped from itssupport so as not to produce too great a separation of the images. Amore pleasing and truthful appearance results when the finishedtransparency in two colors only is viewed before an incandescentartificial light as such light contains less blue than daylight andapproximates closely to that transmitted by the taking filters.

Une of the practical advantages of my method is that by it a positivedye image or picture is obtained directly from the black and whitenegative without first converting the latter into a positive although,obviously, if master positives are made, any desired number of duplicatecolor positives may be printed therefrom.

Tn practising my invention, care should be exercised, in the firstplace, in obtaining good negatives, particularly avoiding overexposure,and the drying step before dyeing is an important one, as previouslypointed out.

The behavior of the sensitive film when gelatin is used as the vehiclefor the silver, under treatment in the bleaching and tanbath ischaracteristic to some extent of other substances 01" the colloid roup,but I recommend the use of gelatin, a one.

as invention:

L The method of making photographs in color, which consists in preparingtwo photographic negative images of the subject on gelatin lightsensitive films by the action of difierently colored lights, saidnegatives being otherwise duplicates of each other, bleaching anddifierentially tanning the gelatin of each according to the lightgradations it has recorded, subjecting each of the two films to theaction of a different dye, said films having been fixed at some stageafter bleaching and superposing the films with the images in register,whereby when said films are viewed by transmitted light in suchsuperposed registering relationship, their combined color efi'ects aremade apparent.

2. The method of making photographic reproductions in colors whichconsists in preparing two photographic negative images of the subject onsensitized gelatin films, one through a red screen or filter and theother through a green screen or filter, said negatives being otherwiseduplicates of each other, developing the images, bleaching anddifierentially tanning the gelatin of each according to the lightgradations it has recorded, dyeing the film exposed through the greenfilter red and the film exposed through the red filter green, fixing thefilms at some stage after bleaching, and finally placing them insuperposed registering relationship whereby their combined color efiectsmay be viewed by transmitted light.

3. The method of making photographic reproductions in colors whichconsists in preparing two photographic negative images 7 color effectsmay be viewed by transmitted light.

4. The method of making photographic reproductions in colors whichconsists in preparing two photographic negative images of the subject ongelatin light sensitive films by the action of differently coloredlights, said negatives being otherwise duplicates of each other,developin the films, bleaching and difierentially tanning the gelatin oieach according to the light gradations it has re corded, fixing thefilms, washing and drying the films, dyeing the films different colorsappropriate to their respective tanned color values after-such drying,fixing the dyes in the films and finally placing the films in superposedregistering, relationship whereby their combined color efiects may beviewed by transmitted light.

5. The method of making photographic reproductions in colors whichconsists in preparing two photographic negative images of the subject ongelatin light sensitive films by the action of difi'erently coloredlights, said negatives being otherwise duplicates of each other,developing the films, bleaching the films in a solution composed ofpotassium ferricyanid, potassium bromid, potassium bichromate, aceticacid and potassium alum substantially as described, thereby tanning thegelatin of each according to the light gradation it has recorded, fixingthe films, dyeing the films difierent colors appropriate to theirrespective tanned color values, fixing the dyes in the films and finallyplacing the films in superposed registering relationship whereby theircombined pollolr effects may be viewed by transmitted ig t.

6. The method of making photographic reproductions in colors whichconsists in preparing two photographic negative images of the subject ongelatin light sensitive films by the action of difierently coloredlights, said negatives being otherwise duplicates of each other,developing the films, bleaching lid and difierentially tanning thegelatin of each according to the light gradations it has recorded,dyeing the untanned portions of the films different colors appropriateto their respective tanned color values, fixing the color in the d edfilms against clifiusion loy means of an acid bath, and finally placingthem superposed. registering relationship whereby their combined colorefiects may be viewed transmitted light.

7. The method oi making photographs in colors which consists inpreparing two photographic negative images of the subject on gelatinfilms sensitized by silver bromoiodid of silver, and each havingrecorded thereon the action of a difierent but complementary coloredlight, said negatives being otherwise duplicates of each other,subjecting each film to the action of a bleaching and tanning bathsubstantially such as described, fixing the film to remove the silversalts, subjecting each film to the action of a dye, the

3 e12 patent may he ohieinerl for five cents each, by addressing the"Commissioner dyes for each film being complementary in color to thelight recorded on the originai negative, and superposing the film withimages in register.

8. As an article of manufacture, phetographic reproduction in colorsconsisting of a transparency formed of two superposed duplicate imagesin gelatin constituting dif- J OHN G. CAPSTAF Witnesses:

RUSSELL B. GRIFFITH, HARRIET Cl. Var.

Washington, D. C.

